Which IMs don't sell out?

Just sold out yesterday.  Other then that I am pretty sure they all do, except maybe the ones in Europe/Asia

Yeah, any IM, for that matter. 

I was asking since I recently signed up for a half (not full) IM, and it's a non  IM branded event (Big Kahuna iN Santa Cruz). Didn't think it was going to sell out since I signed up only about 3 months before the race, but sure enough, a friend told me it sold out. Makes me realize that if I'm planning to do an IM next year, I better get on the ball in terms of signing up and planning ASAP.

Continental us or Canada is my preference, but would love to hear about all of 'em.

FYI - Big Kahuna is still open. I've done it two years in a row. I usually decide a week or so before the race to sign up. Never heard about it selling out. 

Well, at the moment I can think of ~12 IM distance races that have yet to sell out.  Or sell 100 slots for that matter.

If you like to be lonely HITS series would be easy to get into late.

If you gave me the option to bail on the run midway I'd probably end up doing a lot of aqua bikes.

Woops - you're right - race still open! Not sure where my friend got the misinformation.

What if it gave you the option to bail at the half way point through the run to avoid a serious injury but still get an official result rather than a DNF?

Ironman St. George never sold out in its 3 years of existence. Probably why its no longer 140.6. 

Check out the Rev3 full events. Rev3 does an excellent job.

Beach to Battleship may sell out but its easy to get into and its a great race.

Great Floridian full is also supposed to be a well ran event.

A new one that has caught my eye is the Bone Island full in Key West. Its a Jan. 2013 race. New race but the company doing it puts on other excellent events.